MarcoPolo - load_record()

This function loads a record from the database.

Loading Records

Eventually, you'll want to operate on records from within your Elixir application. Using this function, you can retrieve records from the database by their Record ID's.

Syntax

load_record(<conn>, <record-id>, <opts>)

• <conn> Defines the database connection.
• <record-id> Defines the Record ID.
• <opts> Defines addtional options for the function. For more information on the available options, see the Options section below.

Options

This function supports a series of additional options defined through the final argument.

• :fetch_plan Defines a fetch plan.
• :ignore_cache Defines whether you want to ignore the cache. It defaults to true.
• :load_tombstones Defines whether you want to load information on deleted records. It defaults to false.
• :if_version_not_latest Defines whether you want to load the record in cases where the provided version is not the latest. This functionality was introduced in version 2.1 of OrientDB.
• :version Defines the record version that you want to load.
• :timeout Defines the timeout value in milliseconds. In the event that the query takes lnger than the allotted time, MarcoPolo sends an exit signal to the calling process.

Return Values

When the operation is successful, the function returns the tuple {:ok, response}. The variable itself is a tuple that contains two elements: the loaded record and the set of records linked to it. You can control the number and depth of linked records using the :fetch_plan option.

In the event that the operation fails, it returns the tuple {:error, message}, where the variable provides the exception message.

Example

Picture an environmental monitoring application where various sensors on write to particular clusters in your database. For each sensor you have a record defining what it monitors and where it is located, and edges that connect to separate vertices noting the readings taken at particular times. You might use a function like the below to retrieve histories on particular sensors.

@doc """ Retrieves sensor data """
def fetch_data(conn, cluster, id) do

    # Log Operation
    IO.puts("Loading Records")


    # Create Record ID
    rid = MarcoPolo.RID( cluster_id: cluster, position: id)

    # Define Options
    options = [fetch_plan: "*.-1"]

    # Load Record
    MarcoPolo.load_record(conn, rid, options) 

end